Application windows can be displayed in a graphical user interface (GUI) with various attributes, such as drop shadows. A drop shadow is an element that can be displayed at one or more edges of an application window. The drop shadow can be designed as a visual effect that looks like the shadow of an object. A viewer perceives that the object is raised above the objects behind it. A drop shadow of an object can be drawn as a gray or black area underneath and offset from the object. For example, the drop shadow can be a copy of the object in black or gray that is drawn in a slightly different position. A drop shadow effect can also be achieved by darkening the colors of pixels where a user would expect a shadow to be cast rather than drawing a gray shadow. To produce a more realistic shadow, the edges of the shadow can be softened, for example, by adding a blur, such as a Gaussian blur, to the shadow.